1. Field of the Invention
The present invention relates to a sealing sheet configured to prevent leakage of liquid into and out of a device, and to a liquid ejection head and an inkjet apparatus using the sealing seat.
2. Description of the Related Art
Japanese Patent Application Publication No. 2004-095224 discloses liquid leakage sensors for detecting leakage of acidic liquid, such as battery liquid, and an electrical insulating material used in the liquid leakage sensors. One of the liquid leakage sensors has a structure in which band-shaped first and second conductors are arranged in parallel at an interval apart on a sheet-shaped base material, and are covered with a covering layer. The covering layer is made of an electrical insulating material of which the electrical insulating properties decline upon reaction with the battery liquid. The other of the liquid leakage sensors has a structure in which a bonding layer made of the electrical insulating material is arranged between a first conductor layer and a second conductor layer, which are permeable to the acidic liquid, and the insulating properties of the electrical insulating material decline upon reaction with the acidic liquid.
Japanese Patent Application Publication No. 2004-095224 proposes electric circuit compositions for electrically detecting the battery liquid leaking out; however, the proposed liquid leakage sensors are constituted of the members permeable to the liquid, and the covering layers are made of the material that dissolves upon reacting with the battery liquid, which means that the sensors themselves do not serve as sealing members to prevent leakage of the liquid.
For example, in an inkjet head, it is necessary to prevent leakage of internal liquids (e.g., inks or a flow channel cleaning liquid) from the internal flow channels in the inkjet head structure. Moreover, in a case where a cleaning liquid is applied to a nozzle surface (ejection surface) of the inkjet head to clean the nozzle surface soiled by ink ejection, if the external liquids including the cleaning liquid and the previously ejected inks, and the like, leak into the inkjet head and adhere to the piezoelectric elements and the drive circuit wiring, then there is a problem in that the ejection circuit system breaks down.